Microstructure and wear resistance of AlCrFeNiMo0.5Six high-entropy alloy coatings prepared by laser cladding

Abstract

In recent years, the coating prepared by laser cladding has attracted much attention in the field of wear research. In this work, AlCrFeNiMo0.5Six (x=0, 0.5, 1.0, 1.5, 2.0) high-entropy alloy coatings were designed and prepared on Q235 steel by laser cladding. The effect of Si content on microstructure, microhardness and wear resistance of the coatings was studied in detail. The results indicate that the AlCrFeNiMo0.5Six high-entropy alloy coatings show an excellent bonding between substrate and the cladding layer. The AlCrFeNiMo0.5Six coatings are composed of nano-precipitated phase with BCC structure and matrix with ordered B2 structure. With the addition of Si, the white phase (Cr, Mo)3Si with cubic structure appears in the interdendritic, and the morphology of the coating (x=2.0) transforms into lamellar eutectic-like structures. The addition of Si enhances the microhardness and significantly improves the wear resistance of the coatings. As x increases from 0 to 2.0, the average hardness of the cladding zone increases from 632 HV to 835 HV, and the wear rate decreases from 1.64×10−5 mm3·(N·m)−1 to 5.13×10−6 mm3·(N·m)−1. When x≥1.5, the decreasing trend of the wear rate gradually slows down. The wear rates of Si1.5 and Si2.0 coatings are 5.85×10−6 mm3·(N·m)−1 and 5.13×10−6 mm3·(N·m)−1, respectively, which is an order of magnitude lower than that of Q235 steel.